openstack/nova
Code Issues Proposed changes

Merge "Implement discard for file backed memory"

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This commit is contained in:
Zuul 2018-06-22 05:07:58 +00:00 committed by Gerrit Code Review
commit 13ae64f203
10 changed files with 300 additions and 9 deletions
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6
doc/source/admin/file-backed-memory.rst
View File

@ -21,6 +21,10 @@ file-backed memory to placement in place of the total system memory capacity.
This allows the node to run more instances than would normally fit
within system memory.
When available in libivrt and qemu, instance memory will be discarded by qemu
at shutdown by calling madvise(MADV_REMOVE), to avoid flushing any dirty memory
to the backing store on exit.
To enable file-backed memory, follow the steps below:
#. `Configure the backing store`_
@ -39,9 +43,11 @@ Prerequisites and Limitations
Libvirt
File-backed memory requires libvirt version 4.0.0 or newer
Discard capability requires libvirt ersion 4.4.0 or newer
Qemu
File-backed memory requires qemu version 2.6.0 or newer
Discard capability requires qemu version 2.10.0 or newer
Memory overcommit
File-backed memory is not compatible with memory overcommit.

9
nova/objects/migrate_data.py
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@ -134,7 +134,8 @@ class LibvirtLiveMigrateData(LiveMigrateData):
# Version 1.5: Added src_supports_native_luks
# Version 1.6: Added wait_for_vif_plugged
# Version 1.7: Added dst_wants_file_backed_memory
VERSION = '1.7'
# Version 1.8: Added file_backed_memory_discard
VERSION = '1.8'
fields = {
'filename': fields.StringField(),
@ -155,12 +156,18 @@ class LibvirtLiveMigrateData(LiveMigrateData):
'supported_perf_events': fields.ListOfStringsField(),
'src_supports_native_luks': fields.BooleanField(),
'dst_wants_file_backed_memory': fields.BooleanField(),
# file_backed_memory_discard is ignored unless
# dst_wants_file_backed_memory is set
'file_backed_memory_discard': fields.BooleanField(),
}
def obj_make_compatible(self, primitive, target_version):
super(LibvirtLiveMigrateData, self).obj_make_compatible(
primitive, target_version)
target_version = versionutils.convert_version_to_tuple(target_version)
if target_version < (1, 8):
if 'file_backed_memory_discard' in primitive:
del primitive['file_backed_memory_discard']
if target_version < (1, 7):
if 'dst_wants_file_backed_memory' in primitive:
del primitive['dst_wants_file_backed_memory']

6
nova/tests/unit/objects/test_migrate_data.py
View File

@ -220,7 +220,9 @@ class _TestLibvirtLiveMigrateData(object):
instance_relative_path='foo/bar',
graphics_listen_addrs={'vnc': '127.0.0.1'},
serial_listen_addr='127.0.0.1',
bdms=[test_bdmi])
bdms=[test_bdmi],
dst_wants_file_backed_memory=True,
file_backed_memory_discard=True)
obj2 = migrate_data.LibvirtLiveMigrateData()
obj2.from_legacy_dict(obj.to_legacy_dict(pre_migration_result=True))
self.assertEqual(obj.to_legacy_dict(),
@ -256,6 +258,8 @@ class _TestLibvirtLiveMigrateData(object):
self.assertNotIn('src_supports_native_luks', primitive)
primitive = data(obj.obj_to_primitive(target_version='1.6'))
self.assertNotIn('dst_wants_file_backed_memory', primitive)
primitive = data(obj.obj_to_primitive(target_version='1.7'))
self.assertNotIn('file_backed_memory_discard', primitive)
def test_bdm_obj_make_compatible(self):
obj = migrate_data.LibvirtLiveMigrateBDMInfo(

2
nova/tests/unit/objects/test_objects.py
View File

@ -1114,7 +1114,7 @@ object_data = {
'InstancePCIRequest': '1.2-6344dd8bd1bf873e7325c07afe47f774',
'InstancePCIRequests': '1.1-65e38083177726d806684cb1cc0136d2',
'LibvirtLiveMigrateBDMInfo': '1.1-5f4a68873560b6f834b74e7861d71aaf',
'LibvirtLiveMigrateData': '1.7-746b3163f022f8811da62afa035ecf66',
'LibvirtLiveMigrateData': '1.8-7806711ede43f4d0afd246d045b7d726',
'KeyPair': '1.4-1244e8d1b103cc69d038ed78ab3a8cc6',
'KeyPairList': '1.3-94aad3ac5c938eef4b5e83da0212f506',
'MemoryDiagnostics': '1.0-2c995ae0f2223bb0f8e523c5cc0b83da',

2
nova/tests/unit/virt/libvirt/test_config.py
View File

@ -3410,12 +3410,14 @@ class LibvirtConfigGuestMemoryBackingTest(LibvirtConfigBaseTest):
obj.sharedaccess = True
obj.allocateimmediate = True
obj.filesource = True
obj.discard = True
xml = obj.to_xml()
self.assertXmlEqual(xml, """
<memoryBacking>
<source type="file"/>
<access mode="shared"/>
<allocation mode="immediate"/>
<discard />
</memoryBacking>""")

189
nova/tests/unit/virt/libvirt/test_driver.py
View File

@ -2446,6 +2446,54 @@ class LibvirtConnTestCase(test.NoDBTestCase,
self.assertTrue(result.filesource)
self.assertTrue(result.allocateimmediate)
@mock.patch.object(fakelibvirt.Connection, 'getVersion')
@mock.patch.object(fakelibvirt.Connection, 'getLibVersion')
def test_get_guest_memory_backing_config_file_backed_discard(self,
mock_lib_version, mock_version):
self.flags(file_backed_memory=1024, group='libvirt')
mock_lib_version.return_value = versionutils.convert_version_to_int(
libvirt_driver.MIN_LIBVIRT_FILE_BACKED_DISCARD_VERSION)
mock_version.return_value = versionutils.convert_version_to_int(
libvirt_driver.MIN_QEMU_FILE_BACKED_DISCARD_VERSION)
result = self._test_get_guest_memory_backing_config(
None, None, None
)
self.assertTrue(result.discard)
@mock.patch.object(fakelibvirt.Connection, 'getVersion')
@mock.patch.object(fakelibvirt.Connection, 'getLibVersion')
def test_get_guest_memory_backing_config_file_backed_discard_libvirt(self,
mock_lib_version, mock_version):
self.flags(file_backed_memory=1024, group='libvirt')
mock_lib_version.return_value = versionutils.convert_version_to_int(
libvirt_driver.MIN_LIBVIRT_FILE_BACKED_DISCARD_VERSION) - 1
mock_version.return_value = versionutils.convert_version_to_int(
libvirt_driver.MIN_QEMU_FILE_BACKED_DISCARD_VERSION)
result = self._test_get_guest_memory_backing_config(
None, None, None
)
self.assertFalse(result.discard)
@mock.patch.object(fakelibvirt.Connection, 'getVersion')
@mock.patch.object(fakelibvirt.Connection, 'getLibVersion')
def test_get_guest_memory_backing_config_file_backed_discard_qemu(self,
mock_lib_version, mock_version):
self.flags(file_backed_memory=1024, group='libvirt')
mock_lib_version.return_value = versionutils.convert_version_to_int(
libvirt_driver.MIN_LIBVIRT_FILE_BACKED_DISCARD_VERSION)
mock_version.return_value = versionutils.convert_version_to_int(
libvirt_driver.MIN_QEMU_FILE_BACKED_DISCARD_VERSION) - 1
result = self._test_get_guest_memory_backing_config(
None, None, None
)
self.assertFalse(result.discard)
def test_get_guest_memory_backing_config_file_backed_hugepages(self):
self.flags(file_backed_memory=1024, group="libvirt")
host_topology = objects.NUMATopology(
@ -8561,7 +8609,8 @@ class LibvirtConnTestCase(test.NoDBTestCase,
"disk_over_commit": False,
"block_migration": True,
"is_volume_backed": False,
"dst_wants_file_backed_memory": False},
"dst_wants_file_backed_memory": False,
"file_backed_memory_discard": False},
matchers.DictMatches(return_value.to_legacy_dict()))
@mock.patch.object(objects.Service, 'get_by_compute_host')
@ -8595,7 +8644,8 @@ class LibvirtConnTestCase(test.NoDBTestCase,
"disk_over_commit": True,
"block_migration": True,
"is_volume_backed": False,
"dst_wants_file_backed_memory": False},
"dst_wants_file_backed_memory": False,
"file_backed_memory_discard": False},
matchers.DictMatches(return_value.to_legacy_dict()))
@mock.patch.object(objects.Service, 'get_by_compute_host')
@ -8626,7 +8676,8 @@ class LibvirtConnTestCase(test.NoDBTestCase,
"disk_over_commit": False,
"disk_available_mb": 409600,
"is_volume_backed": False,
"dst_wants_file_backed_memory": False},
"dst_wants_file_backed_memory": False,
"file_backed_memory_discard": False},
matchers.DictMatches(return_value.to_legacy_dict()))
@mock.patch.object(objects.Service, 'get_by_compute_host')
@ -8699,7 +8750,8 @@ class LibvirtConnTestCase(test.NoDBTestCase,
"disk_over_commit": False,
"disk_available_mb": 1024,
"is_volume_backed": False,
"dst_wants_file_backed_memory": False}
"dst_wants_file_backed_memory": False,
"file_backed_memory_discard": False}
self.assertEqual(expected_result, result.to_legacy_dict())
@mock.patch.object(objects.Service, 'get_by_compute_host')
@ -8734,7 +8786,8 @@ class LibvirtConnTestCase(test.NoDBTestCase,
"disk_over_commit": False,
"disk_available_mb": 1024,
"is_volume_backed": False,
"dst_wants_file_backed_memory": False},
"dst_wants_file_backed_memory": False,
"file_backed_memory_discard": False},
matchers.DictMatches(return_value.to_legacy_dict()))
@mock.patch.object(objects.Service, 'get_by_compute_host')
@ -8770,6 +8823,132 @@ class LibvirtConnTestCase(test.NoDBTestCase,
self.assertTrue(return_value.dst_wants_file_backed_memory)
@mock.patch.object(fakelibvirt.Connection, 'getVersion')
@mock.patch.object(fakelibvirt.Connection, 'getLibVersion')
@mock.patch.object(objects.Service, 'get_by_compute_host')
@mock.patch.object(libvirt_driver.LibvirtDriver,
'_create_shared_storage_test_file')
@mock.patch.object(fakelibvirt.Connection, 'compareCPU')
def test_check_can_live_migrate_dest_file_backed_discard(
self, mock_cpu, mock_test_file, mock_svc, mock_lib_version,
mock_version):
self.flags(file_backed_memory=1024, group='libvirt')
mock_lib_version.return_value = versionutils.convert_version_to_int(
libvirt_driver.MIN_LIBVIRT_FILE_BACKED_DISCARD_VERSION)
mock_version.return_value = versionutils.convert_version_to_int(
libvirt_driver.MIN_QEMU_FILE_BACKED_DISCARD_VERSION)
instance_ref = objects.Instance(**self.test_instance)
instance_ref.vcpu_model = test_vcpu_model.fake_vcpumodel
drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
compute_info = {'disk_available_least': 400,
'cpu_info': 'asdf',
}
filename = "file"
svc = objects.Service()
svc.version = 32
mock_svc.return_value = svc
# _check_cpu_match
mock_cpu.return_value = 1
# mounted_on_same_shared_storage
mock_test_file.return_value = filename
# No need for the src_compute_info
return_value = drvr.check_can_live_migrate_destination(self.context,
instance_ref, None, compute_info, False)
self.assertTrue(return_value.dst_wants_file_backed_memory)
self.assertTrue(return_value.file_backed_memory_discard)
@mock.patch.object(fakelibvirt.Connection, 'getVersion')
@mock.patch.object(fakelibvirt.Connection, 'getLibVersion')
@mock.patch.object(objects.Service, 'get_by_compute_host')
@mock.patch.object(libvirt_driver.LibvirtDriver,
'_create_shared_storage_test_file')
@mock.patch.object(fakelibvirt.Connection, 'compareCPU')
def test_check_can_live_migrate_dest_file_backed_discard_bad_libvirt(
self, mock_cpu, mock_test_file, mock_svc, mock_lib_version,
mock_version):
self.flags(file_backed_memory=1024, group='libvirt')
mock_lib_version.return_value = versionutils.convert_version_to_int(
libvirt_driver.MIN_LIBVIRT_FILE_BACKED_DISCARD_VERSION) - 1
mock_version.return_value = versionutils.convert_version_to_int(
libvirt_driver.MIN_QEMU_FILE_BACKED_DISCARD_VERSION)
instance_ref = objects.Instance(**self.test_instance)
instance_ref.vcpu_model = test_vcpu_model.fake_vcpumodel
drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
compute_info = {'disk_available_least': 400,
'cpu_info': 'asdf',
}
filename = "file"
svc = objects.Service()
svc.version = 32
mock_svc.return_value = svc
# _check_cpu_match
mock_cpu.return_value = 1
# mounted_on_same_shared_storage
mock_test_file.return_value = filename
# No need for the src_compute_info
return_value = drvr.check_can_live_migrate_destination(self.context,
instance_ref, None, compute_info, False)
self.assertTrue(return_value.dst_wants_file_backed_memory)
self.assertFalse(return_value.file_backed_memory_discard)
@mock.patch.object(fakelibvirt.Connection, 'getVersion')
@mock.patch.object(fakelibvirt.Connection, 'getLibVersion')
@mock.patch.object(objects.Service, 'get_by_compute_host')
@mock.patch.object(libvirt_driver.LibvirtDriver,
'_create_shared_storage_test_file')
@mock.patch.object(fakelibvirt.Connection, 'compareCPU')
def test_check_can_live_migrate_dest_file_backed_discard_bad_qemu(
self, mock_cpu, mock_test_file, mock_svc, mock_lib_version,
mock_version):
self.flags(file_backed_memory=1024, group='libvirt')
mock_lib_version.return_value = versionutils.convert_version_to_int(
libvirt_driver.MIN_LIBVIRT_FILE_BACKED_DISCARD_VERSION)
mock_version.return_value = versionutils.convert_version_to_int(
libvirt_driver.MIN_QEMU_FILE_BACKED_DISCARD_VERSION) - 1
instance_ref = objects.Instance(**self.test_instance)
instance_ref.vcpu_model = test_vcpu_model.fake_vcpumodel
drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
compute_info = {'disk_available_least': 400,
'cpu_info': 'asdf',
}
filename = "file"
svc = objects.Service()
svc.version = 32
mock_svc.return_value = svc
# _check_cpu_match
mock_cpu.return_value = 1
# mounted_on_same_shared_storage
mock_test_file.return_value = filename
# No need for the src_compute_info
return_value = drvr.check_can_live_migrate_destination(self.context,
instance_ref, None, compute_info, False)
self.assertTrue(return_value.dst_wants_file_backed_memory)
self.assertFalse(return_value.file_backed_memory_discard)
@mock.patch.object(objects.Service, 'get_by_compute_host')
@mock.patch.object(fakelibvirt.Connection, 'compareCPU')
def test_check_can_live_migrate_dest_incompatible_cpu_raises(

74
nova/tests/unit/virt/libvirt/test_migration.py
View File

@ -595,6 +595,80 @@ class UtilityMigrationTestCase(test.NoDBTestCase):
</memoryBacking>
</domain>"""))
def test_update_memory_backing_discard_add(self):
data = objects.LibvirtLiveMigrateData(
dst_wants_file_backed_memory=True, file_backed_memory_discard=True)
xml = """<domain>
<memoryBacking>
<source type="file"/>
<access mode="shared"/>
<allocation mode="immediate"/>
</memoryBacking>
</domain>"""
doc = etree.fromstring(xml)
res = etree.tostring(migration._update_memory_backing_xml(doc, data),
encoding='unicode')
self.assertThat(res, matchers.XMLMatches("""<domain>
<memoryBacking>
<source type="file"/>
<access mode="shared"/>
<allocation mode="immediate"/>
<discard />
</memoryBacking>
</domain>"""))
def test_update_memory_backing_discard_remove(self):
data = objects.LibvirtLiveMigrateData(
dst_wants_file_backed_memory=True,
file_backed_memory_discard=False)
xml = """<domain>
<memoryBacking>
<source type="file"/>
<access mode="shared"/>
<allocation mode="immediate"/>
<discard />
</memoryBacking>
</domain>"""
doc = etree.fromstring(xml)
res = etree.tostring(migration._update_memory_backing_xml(doc, data),
encoding='unicode')
self.assertThat(res, matchers.XMLMatches("""<domain>
<memoryBacking>
<source type="file"/>
<access mode="shared"/>
<allocation mode="immediate"/>
</memoryBacking>
</domain>"""))
def test_update_memory_backing_discard_keep(self):
data = objects.LibvirtLiveMigrateData(
dst_wants_file_backed_memory=True, file_backed_memory_discard=True)
xml = """<domain>
<memoryBacking>
<source type="file"/>
<access mode="shared"/>
<allocation mode="immediate"/>
<discard />
</memoryBacking>
</domain>"""
doc = etree.fromstring(xml)
res = etree.tostring(migration._update_memory_backing_xml(doc, data),
encoding='unicode')
self.assertThat(res, matchers.XMLMatches("""<domain>
<memoryBacking>
<source type="file"/>
<access mode="shared"/>
<allocation mode="immediate"/>
<discard />
</memoryBacking>
</domain>"""))
class MigrationMonitorTestCase(test.NoDBTestCase):
def setUp(self):

3
nova/virt/libvirt/config.py
View File

@ -2054,6 +2054,7 @@ class LibvirtConfigGuestMemoryBacking(LibvirtConfigObject):
self.filesource = False
self.sharedaccess = False
self.allocateimmediate = False
self.discard = False
def format_dom(self):
root = super(LibvirtConfigGuestMemoryBacking, self).format_dom()
@ -2073,6 +2074,8 @@ class LibvirtConfigGuestMemoryBacking(LibvirtConfigObject):
root.append(etree.Element("access", mode="shared"))
if self.allocateimmediate:
root.append(etree.Element("allocation", mode="immediate"))
if self.discard:
root.append(etree.Element("discard"))
return root

9
nova/virt/libvirt/driver.py
View File

@ -288,6 +288,8 @@ MIN_QEMU_LUKS_VERSION = (2, 6, 0)
MIN_LIBVIRT_FILE_BACKED_VERSION = (4, 0, 0)
MIN_QEMU_FILE_BACKED_VERSION = (2, 6, 0)
MIN_LIBVIRT_FILE_BACKED_DISCARD_VERSION = (4, 4, 0)
MIN_QEMU_FILE_BACKED_DISCARD_VERSION = (2, 10, 0)
VGPU_RESOURCE_SEMAPHORE = "vgpu_resources"
@ -4736,6 +4738,10 @@ class LibvirtDriver(driver.ComputeDriver):
membacking.filesource = True
membacking.sharedaccess = True
membacking.allocateimmediate = True
if self._host.has_min_version(
MIN_LIBVIRT_FILE_BACKED_DISCARD_VERSION,
MIN_QEMU_FILE_BACKED_DISCARD_VERSION):
membacking.discard = True
return membacking
@ -6601,6 +6607,9 @@ class LibvirtDriver(driver.ComputeDriver):
data.disk_available_mb = disk_available_mb
data.dst_wants_file_backed_memory = \
CONF.libvirt.file_backed_memory > 0
data.file_backed_memory_discard = (CONF.libvirt.file_backed_memory and
self._host.has_min_version(MIN_LIBVIRT_FILE_BACKED_DISCARD_VERSION,
MIN_QEMU_FILE_BACKED_DISCARD_VERSION))
return data

9
nova/virt/libvirt/migration.py
View File

@ -236,12 +236,16 @@ def _update_memory_backing_xml(xml_doc, migrate_data):
"""
old_xml_has_memory_backing = True
file_backed = False
discard = False
memory_backing = xml_doc.findall('./memoryBacking')
if 'dst_wants_file_backed_memory' in migrate_data:
file_backed = migrate_data.dst_wants_file_backed_memory
if 'file_backed_memory_discard' in migrate_data:
discard = migrate_data.file_backed_memory_discard
if not memory_backing:
# Create memoryBacking element
memory_backing = etree.Element("memoryBacking")
@ -249,7 +253,7 @@ def _update_memory_backing_xml(xml_doc, migrate_data):
else:
memory_backing = memory_backing[0]
# Remove existing file-backed memory tags, if they exist.
for name in ("access", "source", "allocation"):
for name in ("access", "source", "allocation", "discard"):
tag = memory_backing.findall(name)
if tag:
memory_backing.remove(tag[0])
@ -263,6 +267,9 @@ def _update_memory_backing_xml(xml_doc, migrate_data):
memory_backing.append(etree.Element("access", mode="shared"))
memory_backing.append(etree.Element("allocation", mode="immediate"))
if discard:
memory_backing.append(etree.Element("discard"))
if not old_xml_has_memory_backing:
xml_doc.append(memory_backing)